Peter Sinclair has video interview with Andrew Dessler about water vapour and climate. The video doesn’t really say anything all that surprising. We are now reasonably sure that relative humidity remains roughly constant as we warm. This then allows us to constrain the role water vapour and indicates that it will have a net positive effect (it will amplify warming). Clouds are still uncertain, mainly because they can both reflect incoming radiation, cooling the climate, and trap heat, so warming the climate. However, our current understanding is that the net effect is probably that clouds will be a net warming influence.

The real reason I wanted to post the video was to make a slightly different point. Given the above, we have a number of lines of evidence indicating that the equilibrium climate sensitivity (ECS) is probably greater than 2oC. This includes paleo estimates, climate models, but also our basic understanding of the physical processes involved.

As many are aware, there are, however, some studies that suggest that ECS is probably less than 2oC. Many of these are methods that rely on statistical analyses of observations. There is, of course, nothing wrong with these methods, but simply because someone has correctly applied a statistical technique, does not mean the result is correct (or correctly represents reality).

The key point I was wanting to highlight is that if some really think that ECS is probably less than 2oC, then at some point someone is going to have to illustrate what physical processes are involved. At the moment, our understanding is that the various processes involved (clouds, water vapour, lapse rate, …) suggest that the ECS is more likely above 2oC than below. No amount of complicated statistics trumps this kind of understanding.

40 Responses to Water vapour and climate

I tend to think ECS is lower than postulated for several reasons, for example, the heat is transferred into deep water more efficiently than theorized. This is partly based on my observation that the Russel ocean dynamics model matches data much better than other models,

In the end, this isn’t going to be won by having NOAA fiddle with data or issue reams of politically coded reports. The TCR and ECS will eventually be set by climate models that match incoming data. And the data can’t be fiddled ad nauseam, there’s a limit to the “corrections” they make. This applies in particular to satellite data.

I know this concept is a bit alien to politically inclined participants. But in a decade those models which perform better will win in a Darwinian process. I tend to think the lower TCR will win out.

I tend to think ECS is lower than postulated for several reasons, for example, the heat is transferred into deep water more efficiently than theorized. This is partly based on my observation that the Russel ocean dynamics model matches data much better than other models,

This shouldn’t influence ECS. It might influence the TCR-to-ECS ratio, but not ECS itself. That only depends on the fast-feedbacks like water vapour, lapse rate, clouds.

In the end, this isn’t going to be won by having NOAA fiddle with data or issue reams of politically coded reports.

No bias on your part then? Just a warning: the next time you post such a claim without evidence, I will simply delete it.

I know this concept is a bit alien to politically inclined participants.

It’s almost as if you think this doesn’t apply to you?

But in a decade those models which perform better will win in a Darwinian process. I tend to think the lower TCR will win out.

Well it is presumably bigger than 1oC and if you think it’s likely less than 1.5oC we will have to warm slowly over the coming decades. I wouldn’t bet on that, but you’re free to do so if you wish.

Fernando,
Given the limited understanding of the physics demonstrated by your suggestion that more heat transferred to the depths of the ocean implies lower ECS, I don’t see why we should regard your opinion any differently than any other opinion extracted from an alternative orifice. In fact, such transfer may explain why estimates assuming rapid equilibration are systematically low.
What matters is energy in and energy out at TOA.

ATTP, The net effect of clouds on the climate today is to cool the surface by about 5°C (9°F), see e.g.http://isccp.giss.nasa.gov/role.html.
The feedback, as response to a warming, is probably slightly positive; I guess that is what you intended to state.

This is a good point. Deniers used to hinge the low climate sensitivity argument on water vapor somehow being a negative feedback, until the observational evidence that it’s a positive feedback became undeniable. Then they switched to the cloud feedback, for example Lindzen’s iris hypothesis, until that was soundly refuted (which didn’t take long), and then just general handwaving about cloud feedback uncertainties and hence the possibility that clouds could be a substantial negative feedback. Now the evidence for that is quite poor, and they’re out of plausible physical mechanisms for low ECS.

So they just point to the energy budget approach papers by folks like Lewis & Curry. Except even those aren’t withstanding scrutiny by folks like Shindell, Kummer & Dessler, Marvel et al. But it’s a good point that for those papers to be right, there would have to be some physical mechanism for a significant negative feedback that simply hasn’t been identified.

So those who argue for a simple relationship between increasing water content of the atmosphere and storm strength, data do not support such a claim over this multi-decadal period, in this region.

Apart from the strawmanish aroma (and the typical Juniorish plausible deniability of implying a larger truth even with the proper qualification of “over this multi-decadal period, in this region”), that is.

“Mann, Director of Penn State’s Earth System Science Center, explained: “There is peer-reviewed science that now suggests that climate change will lead to more of these intense, blizzard-producing nor’easters, for precisely the reason we’re seeing this massive storm — unusually warm Atlantic ocean surface temperatures (temperatures are in the 70s off the coast of Virginia).”
When you mix extra moisture with “a cold Arctic outbreak (something we’ll continue to get even as global warming proceeds),” as Mann points out, “you get huge amounts of energy and moisture, and monster snowfalls, like we’re about to see here.”
Mann’s bottom line:
“While critics like to claim that these massive winter storms are evidence against climate change, they are actually favored by climate change.”
Trenberth, former head of the Climate Analysis Section at the National Center for Atmospheric Research, agrees: “At present sea surface temperatures are more the 3F above normal over huge expanses (1000 miles) off the NE coast and water vapor in the atmosphere is about 10 to 15% higher as a result. Up to half of this can be attributed to climate change.”
So Superstorm Snowed-In is able to sweep in vastly more water vapor thanks to human-caused warming.
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There is probably a fine distinction to make between a classical strawman.
‘Joshua argues X’
and these types of oblique ‘strawmen’ that people engage in.

“”While critics like to claim that these massive winter storms are evidence against climate change, they are actually favored by climate change.”

“So those who argue for a simple relationship between increasing water content of the atmosphere and storm strength, data do not support such a claim over this multi-decadal period, in this region.”

There should be names for this.. oh wait

“In 2006, Robert Talisse and Scott Aikin expanded the application and use of the straw man fallacy beyond that of previous rhetorical scholars, arguing that the straw man fallacy can take two forms, the original form in which the opponent’s position is misrepresented, which they call the representative form and a new form which they call the selection form.

The selection form focuses on a partial and weaker (and easier to refute) representation of the opponent’s position. Then the easier refutation of this weaker position is claimed to refute the opponent’s complete position. They point out the similarity of the selection form to the fallacy of hasty generalization, in which the refutation of an opposing position that is weaker than the opponent’s is claimed as a refutation of all opposing arguments. Because they have found significantly increased use of the selection form in modern political argumentation, they view its identification as an important new tool for the improvement of public discourse.[14]

Aikin and Casey expanded on this model in 2010, introducing a third form. Referring to the “representative form” as the classic straw man, and the “selection form” as the weak man, a third form is called the hollow man. A hollow man argument is one that is a complete fabrication, where both the viewpoint and the opponent expressing it do not in fact exist, or at the very least the arguer has never encountered them. Such arguments frequently takes the form of vague phrasing such as “some say,” “someone out there thinks” or similar weasel words, or it might attribute a non-existent argument to a broad movement in general, rather than an individual or organization.[15][16]

A variation on the selection form, or “weak man” argument, that combines with an ad hominem is nut picking, a neologism coined by Kevin Drum.[17] A portmanteau of “nut” (i.e., insane person) and cherry picking, nut picking refers to intentionally seeking out extremely fringe, non-representative statements and/or individuals from members of an opposing group and parading these around as evidence of that entire group’s incompetence or irrationality.”

“But in a decade those models which perform better will win in a Darwinian process.”

This process has already taken place over the last 3 decades and you have dismissed their results with a wave of your hand and a not so subtle claim of fraud. Why should any reader believe that another decade of measurements and modeling will change your belief system?

Joshua,
Isn’t Roger’s post a year old? It does seems rather standard. Various argument as to why some events occuring in some relatively small region do not show a trend and cannot be attributed to anthropogenic influences. May even be true, but – as others have pointed out – probably not really all that relevant. We’re adding energy to the system. Do we really expect the extremes not to change in some way? Could they get weaker? Seems unlikely given that there’s more energy. Does warmer air hold more water vapour? Basic physics would suggest that it does.

Maybe Roger really thinks he’s doing some kind of service by pushing back against overly strong claims in the media. It may well be true that this does happen but I don’t really see how we benefit by then presenting an overly simplistic analysis that almost entirely ignores the overall context.

“The salient point is that even when a trend is present, if we’re looking at rare events there may be too few for trends to reach statistical significance. This problem plagues the detection of trends in disasters, and in extreme weather generally. By definition, extreme events are rare — we won’t see very many of them, so we need data for a long time to have enough for conclusions to be reliable.”

Since these events are rare enough, any reduction in data (geographical, temporal) will make trends and their significance even harder to detect.

oneillsinwisconsin,
Thanks, I hadn’t seen that yet. It’s a great post and I think it is important to recognise that not only is detection difficult, because we’re typically dealing with rare events, but attribution is even harder. As you say, if you only consider a particular region or time interval, then it gets even harder. Similarly, looking at damages makes it even more so because then you’re really considering some kind of proxy and one that needs significant adjustments.

A type of nut picking that may deserve due diligence is when a ClimateBall ™ player puts a wedge between two nuts and present his own position as the non-nut position. When done gently, it reminds of Goldilocks. When done more forcefully, it smells of Mr. T. In every case a lukewarm feeling might be felt.

In terms of financial losses, we were somewhat fortunate in 2015: Strong tropical cyclones frequently only hit sparsely populated areas or did not make landfall at all. In the North Atlantic, El Niño helped to curtail the development of heavy storms. Measures to reduce loss susceptibility have also had a positive effect”, explained Peter Höppe, Head of Munich Re’s Geo Risks Research Unit. However, the comparatively low losses are no reason to become complacent: “Scientists believe that in 2016 the strong El Niño phase might be followed by its twin sister, La Niña. Both versions of the climate oscillation ENSO (El Niño/Southern Oscillation) in the Pacific influence weather extremes throughout the world. A La Niña phase would promote the development of hurricanes in the North Atlantic, for example

Funny, I hadn’t noticed the date of Roger’s post…just followed the link from a recent post at WUWT… I did wonder why Roger was posting about climate again, given that he said he was done with it because (paraphrasing) he had been so mistreated. …So that explains the apparent contradiction.

Of course, à la the tweet willard provided, it seems that Roger hasn’t let posting articles about climate change get in the way of his plausible deniability technique (i.e., “Although my tweet makes a clear implication that 2015 proves that there’s no association between ACO2 emissions and damage from extreme weather, I didn’t actually come right out and say that there’s no association between the two”).

“The Serengeti Strategy” is a term coined by climate scientist Michael Mann in which “special interests faced with adverse scientific evidence … target individual scientists rather than take on an entire scientific field at once.” His invention of the analogy must have been an interesting moment, given the context.

[D]espite knowing that Bitcoin could fail all along, the now inescapable conclusion that it has failed still saddens me greatly. The fundamentals are broken and whatever happens to the price in the short term, the long term trend should probably be downwards. I will no longer be taking part in Bitcoin development and have sold all my coins.

Yeah I think an attack normally would consist of accusations of unethical behavior or something egregious,. But I think people here are instead questioning his judgement and or conclusions. I would hope criticizing someone for what they say is not off limits here even if you might end up being wrong.

Yeah I think an attack normally would consist of accusations of unethical behavior or something egregious,.

That is certainly how I would normally interpret it. However, I did today discover an example where someone had used “attack”, but possibly had meant it in the context of “criticise”. It’s possible that there are certain environments where a criticism is seen as an attack. In scientific circles that isn’t normally the case. Criticism can be quite constructive, while “attack” would normally be reserved for something much more serious than just a basic critique.

To be perfectly blunt there is no statement claiming a 1/1 relationship between environmental damage and global temperatures. Just trend lines and error margins. Working against that is of course adaptation, meaning that we’re all spending cash now to forestall future damage. This is an El Nino Year and of course global crops were adjusted to reduce risk.

Maybe Steve McIntyre would like to find the economist/scientist stated that there would be a 1 to 1 correlation?

In the context of this discussion thread, the following caught my eye…

In a flagship risk report, the United Nations said last year that the cost of disasters worldwide had reached an average of $250 billion to $300 billion every year.

But totals reported by big insurance firms tend to come in far below that, as they do not account for losses from repeated, smaller-scale disasters in poorer countries, experts say.

“One of the problems with disaster risk reduction is that even governments haven’t quantified the costs of disasters, and unless they can put a price on it, if you talk to a finance ministry, they have competing priorities,” Glasser said.